White Makes Right? Steven Chu’s Helpful Idea

Energy Secretary Steven Chu made headlines when he proposed ‘soft’ geoengineering by painting roofs and roads white in order to reflect sunlight back into space. That idea might seem absurd to some, but Chu has done the nation a service.

To most people, the idea of “geoengineering” the climate—that is, deliberately altering features of the earth’s environment in ways that would cool the planet—may seem horrifying, if not absurd. I have argued elsewhere that such an attitude is mistaken; global warming itself is little more than an unintentional and uncontrolled geoengineering experiment. Yet it is easy to understand why people may feel uneasy about, say, proposals to distribute large amounts of a known pollutant (sulfur aerosols) in the upper atmosphere to block out enough sunlight to counteract the effects of warming; on a gut level, the idea just sounds scary.

In many locations, white roofs could cut a building’s energy consumption by as much as 20 percent.

In environmental issues, even more than most public policy questions, perception matters. That is why “soft” geoengineering techniques—less ambitious, less disruptive, and less threatening approaches—are important; they get people used to the basic concepts of geoengineering without scaring them. And in so doing, they expand the scope of the climate policy discussion in important ways.

Energy Secretary Steven Chu made headlines last week when he gave a speech at the Nobel Laureate Symposium in London in which he proposed painting roofs and roads white in order to reflect sunlight back into space. This simple way of increasing the Earth’s albedo—and consequently, cooling the planet—is, in fact, a good example of low-tech “soft” geoengineering. (White roofs could also cool houses, reducing the cost and emissions due to air conditioning.) As Chu explained:

If you look at all the buildings and if you make the roofs white, and if you make the pavement more of a concrete type of color rather than a black type of color, and if you do that uniformly, that would be the equivalent of . . . reducing the carbon emissions due to all the cars in the world by 11 years—just taking them off the road for 11 years.

Energy Secretary Steven Chu made headlines when he proposed ‘soft’ geoengineering by painting roofs and roads white in order to reflect sunlight back into space.

Can it really be that simple? Well, yes and no. Practical considerations limit the effectiveness of such an approach; as with green buildings, roofs and roads are not built (or rebuilt) quickly, so it would take many years to implement such changes on an effective scale. Many buildings may be unsuitable for application of this idea, and property owners may find the approach unappealing, particularly if it is not rewarded with emissions credits. And, as any homeowner knows, white roofs—much less white roads—are likely to turn gray with time, reducing their reflectivity. Nevertheless, in many locations, white roofs could cut a building’s energy consumption by as much as 20 percent.

Chu’s proposal might seem preposterous but there is credible science behind the concept. See this paper (or this helpful summary of its conclusions) for an exploration of the potential scope of this idea and its costs and benefits.

Electric power plants and automobiles may be the most visible source of emissions and consequently the most tempting targets for regulators, but ultimately we need to look more broadly at creative ways of reducing the harmful effects of climate change.

White roofs and roads are not going to have much effect on the overall climate in the immediate future—but just talking about these ideas has value. Moving the conversation about climate policy beyond the narrow confines of caps and costs to include more innovative concepts such as adaptation and geoengineering is an important step forward. The Waxman-Markey bill, which would establish a cap on greenhouse gases, may dominate the headlines today, but real success in crafting climate policy will hinge largely upon our ability to take a broader view of the issue. Electric power plants and automobiles may be the most visible source of emissions and consequently the most tempting targets for regulators, but ultimately we need to look more broadly at creative ways of reducing the harmful effects of climate change in the long run. White roofs and roads may sound silly, but the idea has an important role to play in the climate debate.